This invention relates to methods and apparatus for canning food products. More particularly, it relates to methods and apparatus which are suitable for use in home canning operations. Even more particularly, the invention relates to such methods and apparatus which eliminate the need for large enclosed steam retorts.
Home canning of various types of produce, such as fruits and vegetables, has become a popular activity in the United States. While there are many attractive reasons for such home canning, a major disadvantage to the procedure has always been the necessity for pressure cooking the food product within the container. This process has generally involved preparing the food products and placing them in containers, such as glass jars with loosely closed tops, and then placing the container and the product within a pressure cooking vessel, or retort, and then steaming the containers and their contents within the pressure cooker for predetermined periods of time prior to cooling and ultimately removing the containers from the vessel.
The conventional apparatus and method for home canning have suffered from a number of disadvantages, which have discouraged many people from engaging in the home canning process. The disadvantages have included the necessity for expensive and bulky pressure cooking apparatus, as well as the storage of bulky empty jars used therewith. Additionally, the pressure cooking procedure requires substantial time and heating energy to perform, since the entire vessel must be brought up to a temperature sufficient to produce the steam for cooking, and then must be cooled prior to opening. Furthermore, pressure cooking of certain fruits and vegetables in the canning process destroys many desirable characteristics of the food, including crisp textures and retention of vitamins within the fruits and vegetables themselves.